Moolgavkar S H, Luebeck E G
Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
Epidemiology. 1996 Jul;7(4):420-8. doi: 10.1097/00001648-199607000-00014.
We review epidemiologic studies of particulate air pollution and mortality in U.S. cities with respect to important methodologic issues. Many of these studies suffer from serious deficiencies in their control of the confounding effects of other pollutants. As a consequence, the small risks reported to be associated with the particulate component of air pollution could easily be attributed to residual confounding by co-pollutants. Most studies, moreover, have not considered modification of air pollution effects by seasonal factors, making the interpretation of the estimated risks difficult. We use a new analysis of mortality in Philadelphia that considers four pollutants simultaneously as well as seasonal effects to illustrate the methodologic issues raised in this paper. Air pollution, which is a complex mixture, appears to be associated with mortality even at the generally low levels of pollution in U.S. cities, but currently neither the statistical tools nor the biological understanding of mechanisms exists to tease out the contribution made by each component of this mixture. We conclude that it is not possible with the present evidence to show a convincing correlation between particulate air pollution and mortality.
我们针对重要的方法学问题，回顾了美国各城市中有关空气中颗粒物污染与死亡率的流行病学研究。这些研究中有许多在控制其他污染物的混杂效应方面存在严重缺陷。因此，报告中与空气污染颗粒物成分相关的小风险很可能容易归因于共存污染物造成的残余混杂。此外，大多数研究并未考虑季节因素对空气污染影响的修正，这使得对估计风险的解读变得困难。我们对费城的死亡率进行了一项新的分析，该分析同时考虑了四种污染物以及季节效应，以阐明本文提出的方法学问题。空气污染是一种复杂的混合物，即便在美国城市普遍较低的污染水平下，它似乎也与死亡率有关，但目前既没有统计工具，也缺乏对相关机制的生物学理解，无法梳理出这种混合物中各成分的作用。我们得出结论，依据目前的证据，无法证明空气中颗粒物污染与死亡率之间存在令人信服的关联。
